ChatGPT Plus is listed at $20, but the actual price can range from $13 to $27...

https://suprmind.ai/hub/chatgpt/pricing/chatgpt-plus-price/

ChatGPT Plus is listed at $20, but the actual price can range from $13 to $27 depending on where and how you subscribe. Differences come from taxes like VAT or GST and extra charges from app stores